That's probably a bug then :/
Type 'strictness' is an interesting concept in PHP. Officially, it's type loose, all the time implied casting (coercing) can occur, e.g. comparing numbers and strings implicitly works (which is why you can put numbers into strcmp and get answers). As soon as you cannot do a viable casting, then no.
That really comes into play with objects, where if you try to work on an object, it'll go through properties, __get and will implicitly try to involve toString() where applicable - and if it can't be coerced to a string, it'll then throw a type error.